Research On Damage Characteristics Of Pantograph Strips Of High Speed Trains

The rapid development of high-speed railway in China has greatly promoted the growth of national economy,and high-speed railway plays an important role in people’s life.The pantograph catenary system(PCS)provides power supply and its performance has direct impact on safety and reliability of trains.In recent years,with the improvement of railway running speed,more traction power is needed,which also leads to a sharp increase in the pantograph-catenary disconnection.The multiple factors of mechanical,electrical and materials is more complex.The coupling mechanism of multiple factors and the damage mechanism under the combined action of these factors have not been clearly defined,the result is that the damage of crack and the edge pits frequently.Damages under the multi coupling factors have gradually become a decisive factor in the service performance evolution of pantograph and caternary.During the operation of high-speed railway,the uneven temperature distribution of the strip material itself and the mechanical impact between the pantograph and the catenary will aggravate the damage of the pantograph strip.In addition,during the operation of high-speed railway,it is difficult to monitor the temperature and stress inside the strip in real time,and it is also difficult to grasp the dynamic evolution process of the strip internal cracks and edge pits,and it is impossible to judge the service status of the pantograph strip to ensure the safe operation of the railway.Therefore,based on the special operating environment of high-speed railway,this paper establishes the damage extension model of the pantograph strip to study the temperature rise characteristics of the strip and the damage extension process of the strip.Based on the dynamic temperature rise model of the pantograph strip,this paper analyzes the temperature distribution change of the strip under different damage patterns,and explores its influence on the temperature rise of the strip.It is found that the maximum temperature of strip increases by 6%-8% when there is a crack with a length of 4 mm near the contact surface.When there is a 1.5 mm deep pit at the edge of the strip,the maximum temperature of the strip increases by 5%-6%.The increase of temperature will seriously aggravate the abnormal wear and crack extension of the strip.At the same time,the influence of different operating conditions on the temperature characteristics of the strip is simulated and analyzed.The factors affecting the temperature distribution of the strip and their influence degree are analyzed comprehensively,which provides a theoretical reference for judging the service performance of the strip.At the same time,the development trend of strip damage was explored by changing parameters such as electric current,relative sliding speed and initial microcrack morphology of strip.It was found that the higher the temperature of the strip,the faster the crack growth rate.The electric current influence on the crack growth of strip is significant.It is clear that the electric current and the joule heat generated during the train operation are the key factors for the damage extension of the strip.It is of certain reference significance to further improve the mechanical and electrical properties of strip and extend its service life.Based on the understanding of the factors affecting temperature rise and damage of strip,the trapezoidal strip of pantograph after optimizing the profile was proposed.The temperature rise effect and crack extension process of trapezoid strip are analyzed by simulation.It was found that when the extension length of the modified strip was 1 mm,the maximum temperature of the strip decreased by 5%-6%,and the crack growth rate decreased significantly.The effectiveness of the improved profile strip is verified and the theoretical basis is provided for optimal design of strips.